Ingredients

Preparation

Bring beans, onion, lard, epazote, and water to a boil in a 3-quart heavy pot. Reduce heat and simmer, partially covered, until beans are tender, about 1 1/4 hours. Add salt and simmer, uncovered, until enough water is evaporated so that liquid reaches just below level of beans, about 30 minutes.

If using beans for omelet filling: Measure out 1 1/2 cups beans with a slotted spoon and 1/2 cup liquid and mash together in a bowl with a potato masher until creamy. Reserve remaining beans and liquid for another use such as black bean soup.